Google has opened up yet another revenue stream for Android developers with the addition of in-app subscriptions. The feature, which is already live on Google Play, allows you to subscribe to apps and premium features and manage your subscriptions directly from the Google Play interface.

In-app subscriptions builds off of Google Play’s in-app billing foundation established last year. Developers have already seen a significant amount of success with in-app billing, with all but one of the 24 top-grossing apps implementing this feature and overall revenue above and beyond traditional app purchases.

Developers will be able to control the price and billing interval for subscriptions, and Google Play handles the rest. Subs will always auto-renew, sending you an email after the fact. Subscription management is handled in the My Apps section of Google Play, giving you a single destination for viewing and canceling those recurring payments.

Interestingly, Google is also adding an API which will allow developers to authenticate and manage subscriptions outside of Android apps. This means that you could potentially purchase a subscription to a news app, visit the news app’s website, and access the same premium content.

The tools to implement in-app subscriptions are already available to developers, so the first apps should start showing up soon. It does, however, require Google Play v3.5 or higher.

What do you think of in-app subscriptions? Would you prefer to receive notifications before or after the subscription is auto-renewed?